Enum lru_mem::TryInsertError

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pub enum TryInsertError<K, V> {
    OccupiedEntry {
        key: K,
        value: V,
    },
    WouldEjectLru {
        key: K,
        value: V,
        entry_size: usize,
        free_memory: usize,
    },
    EntryTooLarge {
        key: K,
        value: V,
        entry_size: usize,
        max_size: usize,
    },
}

Expand description

An enumeration of the different errors that can occur when calling LruCache.

Variants

`OccupiedEntry`

Fields

key: K

The key of the entry to insert.

value: V

The value of the entry to insert.

This error is raised if the cache already contained an entry with a key equal to the given one.

`WouldEjectLru`

Fields

key: K

The key of the entry to insert.

value: V

The value of the entry to insert.

entry_size: usize

The computed size requirement of the entry if it were in the cache in bytes.

free_memory: usize

The remaining free memory of the cache in bytes.

This error is raised if the cache cannot fit the given entry without ejecting the LRU element.

`EntryTooLarge`

Fields

key: K

The key of the entry which was too large.

value: V

The value of the entry which was too large.

entry_size: usize

The computed size requirement of the entry if it were in the cache in bytes.

max_size: usize

The maximum size of the cache in bytes.

This error is raised if the amount of memory required to store an entry to be inserted is larger than the maximum of the cache.

Implementations

source

impl<K, V> TryInsertError<K, V>

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pub fn entry(&self) -> (&K, &V)

Gets references to the key and value of the entry for which LruCache::try_insert failed.

Example

use lru_mem::LruCache;

let mut cache = LruCache::new(1024);
cache.insert("apple", "sweet").unwrap();
let err = cache.try_insert("apple", "sour").unwrap_err();

assert_eq!((&"apple", &"sour"), err.entry());

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pub fn key(&self) -> &K

Gets a reference to the key of the entry for which LruCache::try_insert failed.

Example

use lru_mem::LruCache;

let mut cache = LruCache::new(1024);
cache.insert("apple", "sweet").unwrap();
let err = cache.try_insert("apple", "sour").unwrap_err();

assert_eq!(&"apple", err.key());

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pub fn value(&self) -> &V

Gets a reference to the value of the entry for which LruCache::try_insert failed.

Example

use lru_mem::LruCache;

let mut cache = LruCache::new(1024);
cache.insert("apple", "sweet").unwrap();
let err = cache.try_insert("apple", "sour").unwrap_err();

assert_eq!(&"sour", err.value());

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pub fn into_entry(self) -> (K, V)

Takes ownership of the error and returns the key and value of the entry for which LruCache::try_insert failed.

Example

use lru_mem::LruCache;

let mut cache = LruCache::new(1024);
cache.insert("apple", "sweet").unwrap();
let err = cache.try_insert("apple", "sour").unwrap_err();

assert_eq!(("apple", "sour"), err.into_entry());

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pub fn into_key(self) -> K

Takes ownership of the error and returns the key of the entry for which LruCache::try_insert failed.

Example

use lru_mem::LruCache;

let mut cache = LruCache::new(1024);
cache.insert("apple", "sweet").unwrap();
let err = cache.try_insert("apple", "sour").unwrap_err();

assert_eq!("apple", err.into_key());

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pub fn into_value(self) -> V

Takes ownership of the error and returns the value of the entry for which LruCache::try_insert failed.

Example

use lru_mem::LruCache;

let mut cache = LruCache::new(1024);
cache.insert("apple", "sweet").unwrap();
let err = cache.try_insert("apple", "sour").unwrap_err();

assert_eq!("sour", err.into_value());